When it came to Mac in August, BioShock Infinite represented a huge change for its venerable franchise. It switched up the combat, trading bizarre weapons for conventional guns and frenetic pacing; it gave players a constant sidekick, Elizabeth; and most strikingly, it moved the action from the undersea nightmare city of Rapture to the (deceptively) sunnier, airborne steampunk metropolis of Columbia. Burial at Sea — Episode One, Infinite's first story-driven add-on, represents a step back on a couple of those points, the biggest being that the setting is once again Rapture — although we get to see it as a gleaming objectivist utopia, before everything really goes crazy.